Every autumn prior to leaf fall, our deciduous trees lose their green colour fading to reveal rich vibrant reds, yellows and oranges. Ever wondered why?
During summer months, the dominate leaf pigment is green chlorophyll. It is the hub of photosynthesis where light energy is used to break down carbon dioxide and water to produce sugars: energy for the tree. As autumn approaches, days shorten and temperatures drop, this energy is stored overwinter as starch in the branches, trunks and roots. But at the same time, chlorophyll production ceases and this pigment is broken down revealing the autumn leaf colours - yellow carotenes including red and pink anthocyanins – that are well known to all of us.
So next time you go for an autumn walk amongst trees you can wonder at this natural process that takes place each and every year.
Russell Ball ; photo: by Brian Cain